Former Prime Minister Manmohan Singh and senior Congress leaders on Monday wrote a letter to President Ram Nath Kovind asking him to caution Prime Minister Narendra Modi about the language used by him during his election campaign in Hubli. Manmohan Singh categorically stated in the letter that Modi's words are threatening and it undermines democratic values. Addressing an election rally on 6th May in Hubli, Narendra Modi had said that the Congress leaders must understand that if they cross their limits, they will have to pay for it.